Omid Mir Syafi, 25, apparently succumbed to apparent heart problems about a month after he was jailed at Tehran's Evin prison for posting a blog challenging Ayatollah Ali Khamenei's support for Hezbollah.
The Times of London reported that Syafi's lawyer said he was told by another Evin inmate that Syafi had been examined in the infirmary by a doctor who allegedly accused him of faking his illness.
Lawyer Mohammad Ali Dadkhah told the newspaper he wanted an autopsy carried out.
There was no official word on Syafi's death from the Iranian government, which has been leaning recently on bloggers and other Internet users seen as being hostile to the country's leadership and their Islamic values.
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